Different types of deadbolts are commercially available. Deadbolts are thrown and retracted by a key-operated cylinder which passes through a hub of the deadbolt assembly. Turning the key turns the hub, which causes an actuator to throw or retract the bolt. Some deadbolts are operated by a single cylinder, wherein the deadbolt is actuated by a key from outside the door and by a turn piece from inside the door. Other deadbolts are operated by a double cylinder, wherein the deadbolt is thrown or retracted by a key from both sides of the door.
Deadbolts are thrown and retracted into a doorpost through a metal plate called a strike. The distance between the strike and the center of the hub is called the backset. In the United States, standard backsets are generally 60 mm or 70 mm. The throw of the deadbolt varies from one lock to another, with the maximum generally being 1 inch.
Deadbolts with an adjustable backset are known. See U.S. Pat. No. 6,837,526 (Markbreit). However, such deadbolts have to be disassembled to change the backset.